Structure and manufacture of a heat sink with high heat transmission

ABSTRACT

The present invention of a structure and manufacture of a heat sink with high heat transmission mainly uses a shear stress caused by stirring to break or crush the solidified arborescent primary crystal at a solid/liquid two-phase area of a aluminum alloy to form a slag fluid with ball-filled solid crushed grit; then ceramic grains are added in and dispersed by the solid grains scattered in the liquid-phase metal; through continuous stirring, the aluminum alloy becomes a fine mixed fluid of ceramic and aluminum alloy without arborescent forms; finally, the external configuration of a heat sink is accomplished through directly compression casting by using the special nature of the aluminum alloy to mold the entire heat sink and to enhance the effect of heat dissipation of the heat sink of the same structure through the high heat transmission efficiency of the ceramic grains.

BACKGROUND OF THE INVENTION

[0001]1) Field of the Invention

[0002] The present invention of a structure and manufacture of a heatsink with high heat transmission aims to provide a heat sink with lightweight and heat transmission higher than that of a conventionalcopper/aluminum alloy to accomplish the external configuration ofvarious heat sinks through direct compression casting for dissipatinghigh heat sources in a central process unit of a computer.

[0003]2) Description of the Prior Art

[0004] Accordingly, with continuously increased operating speed, thepower of a central process unit (CPU) of a computer is also enhanced; atthe same time, more heat sources are generated; the common heat sinkapplied to the CPU mainly uses a heat transmission action to dissipatethe heat source thereof; therefore, heat fins are properly spaced on themain body of the heat sink; the disposition of heat fins increases theair contact area so as to achieve the release of heat sources;therefore, basically, the effect of heat dissipation depends on the heattransmission efficiency of the main body of the heat sink; as a result,the heat sink with an aluminum alloy main body used for a CPU of aconventional computer has been gradually replaced by the copper alloywith higher efficiency of heat transmission.

[0005] However, although the main body of the conventional heat sinkscan be processed into various external configurations through drawing orextruding the copper/aluminum alloy, with limited efficiency of heattransmission of the structure thereof, it fails to meet the heatdissipation demands of a CPU with higher operating speed; moreespecially, in spite of having heat transmission efficiency better thanthe aluminum alloy, the specific gravity of the entire heat sink ofcopper alloy is higher than that of the heat sink of aluminum alloy andthat does not meet the requirements of a lightweight computer.

SUMMARY OF THE INVENTION

[0006] Therefore, the primary objective of the present invention is touse a shear stress caused by stirring to break or crush the solidifiedarborescent primary crystal at a solid/liquid two-phase area of aaluminum alloy to form a slag fluid with ball-filled solid crushed grit;then ceramic grains are added in and dispersed by the solid grainsscattered in the liquid-phase metal; through continuous stirring, thealuminum alloy becomes a fine mixed fluid of ceramic and aluminum alloywithout arborescent forms; finally, the external configuration of a heatsink is accomplished through directly compression casting by using thespecial nature of the aluminum alloy to mold the entire heat sink and toenhance the effect of heat dissipation of the heat sink of the samestructure through the high heat transmission efficiency of the ceramicgrains.

[0007] Another objective of the present invention is to mix a properratio of ceramic grains into the aluminum alloy for tremendouslyreducing the mass of the entire heat sink so as to meet the requirementsof the designing demands of the lightweight computer even more.

[0008] To enable a further understanding the structure and objectives ofthe present invention, the brief description of the drawings below isfollowed by the detailed description of the preferred embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009]FIG. 1 illustrates the tested result obtained by simulating adesk-top computer using the same 80 watt heat source for theconventional copper-made heat sink and the heat sink of the presentinvention.

[0010]FIG. 2 illustrates the tested result obtained by simulating anotebook computer using the same 35 watt heat source for theconventional copper-made heat sink and the heat sink of the presentinvention.

[0011]FIG. 3 is a cross reference table of coefficients of the heat dragobtained through the experiments of the conventional copper-made heatsink and the heat sink of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] The present invention of a structure and manufacture of a heatsink with high heat transmission has the entire heat sink thereofmanufactured into various almost net shapes according to the need of thepractical application; furthermore, ceramic grains in a proper ratio aremixed into the aluminum alloy of a main body of the entire structure soas to use the special nature of the aluminum alloy to mold the entireheat sink and to enhance the effect of heat dissipation of the heat sinkof the same structure through the high heat transmission efficiency ofthe ceramic grains; wherein, the aluminum alloy is composed by freelygrouping AlSi, AlSiCu, AlSiZn, AlSiMg, AlSiCuMg, AlGe, AlGeSi, AlCu,AlMn, AlLi, AlSn and AlPb; the ceramic grains are grains of siliconcarbide with the size of 40-3000 μm.

[0013] Furthermore, the manufacturing of the entire heat sink uses ashear stress caused by stirring to break or crush the solidifiedarborescent primary crystal at a solid/liquid two-phase area of aaluminum alloy to form a slag fluid with ball-filled solid crushed grit;then ceramic grains are added in and dispersed by the solid grainsscattered in the liquid-phase metal; through continuous stirring, thealuminum alloy becomes a fine mixed fluid of ceramic and aluminum alloywithout arborescent forms; finally, the external configuration of a heatsink is accomplished through directly compression casting.

[0014] In the present invention, since a proper ratio of ceramic grainsare mixed into the aluminum alloy, the high heat transmission efficiencyof the ceramic grains is used to enhance the heat dissipation effect ofthe structure of the same form; as indicated in FIGS. 1 to 3, theexperimental comparison between the finished sample of the presentinvention and a conventional copper-made heat sink, the heattransmission efficiency of the heat sink of the present invention is 485W/mK higher than the magnitude of 4000 W/mK of the copper-made heatsink; furthermore, with different contents of the ceramic grains, theheat transmission coefficients of the heat sink of the present inventionare between 150 and 485 W/mK and that can be applied to a centralprocess unit (CPU) with heat source above 85 W or speed of 2.2 GHz;however, the heat transmission coefficient of the conventionalcopper-made heat sink is only 400 W/mK and that can only be used for aCPU with heat source of 80 W at the most; more especially, withdifferent contents of the ceramic grains, the density of the heat sinkof the present invention is between 2.7 and 3.5 g/cm³; to compare with8.6 g/cm³ of the conventional copper-made heat sink, the weight can bereduced about ½ to ⅔; therefore, it meets the requirements of thedesigning demands of a notebook computer even more.

[0015] The present invention of a structure and manufacture of a heatsink with high heat transmission mainly uses a shear stress caused bystirring to break or crush the solidified arborescent primary crystal ata solid/liquid two-phase area of a aluminum alloy to form a slag fluidwith ball-filled solid crushed grit; then ceramic grains are added inand dispersed by the solid grains scattered in the liquid-phase metal;through continuous stirring, the aluminum alloy becomes a fine mixedfluid of ceramic and aluminum alloy without arborescent forms; finally,the external configuration of a heat sink is accomplished throughdirectly compression casting by using the special nature of the aluminumalloy to mold the entire heat sink and to enhance the effect of heatdissipation of the heat sink of the same structure through the high heattransmission efficiency of the ceramic grains; therefore, the presentinvention provides another structure and manufacture of a heat sink withhigher heat transmission and is lawfully submitted to the patentapplication hereby.

[0016] It is of course to be understood that the embodiment describedherein is merely illustrative of the principles of the invention andthat a wide variety of modifications thereto may be effected by personsskilled in the art without departing from the spirit and scope of theinvention as set forth in the following claims.

1. A heat sink with high heat transmission is characterized that theentire heat sink thereof is manufactured into various almost net shapesaccording to the need of the practical application; furthermore, ceramicgrains are mixed in a proper ratio into the aluminum alloy of a mainbody of the entire structure so as to use the special nature of thealuminum alloy to mold the entire heat sink and to enhance the effect ofheat dissipation of the heat sink of the same structure through the highheat transmission efficiency of the ceramic grains
 2. The presentinvention of a heat sink with high heat transmission according to claim1, wherein, the aluminum alloy is composed by freely grouping AlSi,AlSiCu, AlSiZn, AlSiMg, AlSiCuMg, AlGe, AlGeSi, AlCu, AlMn, AlLi, AlSnand AlPb.
 3. The present invention of a heat sink with high heattransmission according to claim 1, wherein, the ceramic grains aregrains of silicon carbide.
 4. The present invention of a heat sink withhigh heat transmission according to claim 1, wherein, the sizes ofgrains of silicon carbides are preferred to be between 40-3000 μm. 5.The present invention of a heat sink with high heat transmissionaccording to claim 1, wherein, the ceramic grains occupy weight ratio0.5-80% of the entire heat sink.
 6. A structure and manufacture of aheat sink with high heat transmission mainly uses a shear stress causedby stirring to break or crush the solidified arborescent primary crystalat a solid/liquid two-phase area of a aluminum alloy to form a slagfluid with ball-filled solid crushed grit; then ceramic grains are addedin and dispersed by the solid grains scattered in the liquid-phasemetal; through continuous stirring, the aluminum alloy becomes a finemixed fluid of ceramic and aluminum alloy without arborescent forms;finally, the external configuration of a heat sink is accomplishedthrough directly compression casting.